Photo: Phil Robinson
Scientists have genetically modified a tomato to produce L-DOPA, a drug used to treat Parkinson’s disease. The researchers suggest this innovation could be an easier and cheaper way to produce the essential medicine in regions where access to the synthesized pharmaceutical is restricted.
Genetically reprogramming certain easily grown plants to generate molecules to use as medicine is not a particularly new idea. Instead of relying on big pharmaceutical companies to synthesize medicines and then deliver them around the world, this strategy combines local plant cultivation with low-cost, simple extraction procedures to offer communities their own production capabilities.
An Australian native tobacco plant is perhaps the most used biofactory due to a novel gene mutation it evolved that essentially switches off its immune system. That tobacco plant has since been engineered to produce everything from flu and polio vaccines to human anti-inflammatory proteins.
Researchers from the John Innes Center in the UK have been working for several years to develop ways to turn tomatoes into tiny drug-producing biofactories as tomato plants are high-yield crops and can be easily grown in many parts of the world. The team’s latest innovation, recently published in the journal Metabolic Engineering, describes how tomatoes can be easily modified to produce L-DOPA, a drug vital to the treatment of Parkinson’s disease.
"The idea is that you can grow tomatoes with relatively little infrastructure,” explains Cathie Martin, corresponding author on the new study. “As GMOs (genetically modified organisms) you could grow them in screen houses, controlled environments with very narrow meshes, so you would not have pollen escape through insects. Then you could scale up at relatively low cost. A local industry could prepare L-DOPA from tomatoes because it's soluble and you can do extractions. Then you could make a purified product relatively low tech which could be dispensed locally."
The proof-of-concept study suggests 150 mg of L-DOPA can be produced from about 1 kg (2.2 lb) of tomatoes. Alongside presenting a novel mode of manufacturing, the study hypothesizes this naturally produced form of the molecule may help reduce the adverse effects seen in some Parkinson’s patients who respond negatively to chemically synthesized L-DOPA.
It’s certainly still very early days for this kind of research but in the future, engineering crops such as tomatoes to produce all manner of useful molecules could give developing nations better access to pharmaceutical technology. Plus, as first author Dario Breitel notes, these engineered crops can present with other unexpected positive outcomes.
"Additionally, there were surprising beneficial effects including improvement in shelf-life and raised levels of amino-acids that we can investigate," says Breitel. “It's a further demonstration of tomato as a strong option for synthetic biology.”